HVAC Issues

Problems with heating and cooling systems can range anywhere from elevated operating costs due to an older, inefficient system to hazardous malfunctions such as a cracked heat exchanger or leaking gas line. It is important to be familiar with your heating and cooling systems and to maintain them properly to avoid any dangerous conditions or costly repairs.
Basic Maintenance
One of the most important things you can do to maintain the efficiency of your heating and cooling systems as well as the air quality in your home is to make sure that your ducts and filters are cleaned or replaced regularly. Duct cleaning takes the expertise of a professional. If you need to find a duct cleaning service in your area, this link is a good resource:
http://www.nadca.com/zm2/search1.asp.

It’s a good idea to also clean your registers and vents regularly between your duct cleaning service’s visits. This can be done easily by cleaning and removing the registers and then vacuuming out the ducts as far as your vacuum hose can reach.

An annual check and servicing of all central air
conditioning systems by a qualified HVAC service company is recommended. In addition, to help attain the maximum comfort and trouble-free service life for their system, homeowners are also advised to following these maintenance and operation guidelines:

-Reset dampers for air conditioning at the start of the cooling season. A damper adjustment is required only if there are separate ducts for the cool air and if the return has both a ceiling and floor register.

-Check to make sure all supply outlets and returns are free from obstructions and dust.

-Clean and/or replace air filters monthly (in season). Service the electronic air cleaner if you have one.

-Check to make sure the condensate drain extending from the evaporator area is draining freely. If there is an overflow pan under the unit, as is the case in many attic installations, be sure the pan is clean and the condensate drain open. If your unit has a condensate pump, keep it clean and working.

-Find a comfortable setting above 78°F and don’t change it.

-Consider installing a programmable or set-back thermostat.

-Make sure all ducts that pass through hot areas such as attics, garages and crawl spaces are insulated.

-Minimize heat gain and hot air infiltration by providing adequate attic insulation and weather-stripping at windows and doors.

-Make sure there is adequate attic ventilation.

-Never operate a house air conditioning system when the outside temperature is below 60°F degrees.

HeatingThere are several easy and inexpensive things you can do yourself to maintain the efficiency of your heating system. If your heating system is a forced air furnace, you should clean or change the filter frequently (every 2-3 weeks during the cold months). If you have a radiator, you will need to “bleed” it of trapped air that would prevent the water from running through the system efficiently. You can do this by opening the bleeding valve until water comes out and then closing it – be careful as the steam and water is very hot. Be sure to have something handy to catch the water. If you have a hot water heating system, you’ll need to clean the boiler by opening the drain valve until the water runs clear. This should be done approximately once a month.

CoolingYou should also do some regular maintenance on your cooling system. For central air conditioners, it’s a good idea to hire a professional service to give your system a check-up before the hot months begin. This usually involves a thorough cleaning of the air conditioning unit, a pressure test to check for leaks and a refill of the coolant if needed. Monthly, you should also check the outdoor unit for blockages and remove any vegetation growing around it that could interfere with its proper functioning. You should also clean or change the filter and check the condensate drain at least monthly. For window units, you should clean or replace the filter at least monthly, bi-weekly during the hottest months. You should also check the condensate drain to make sure that all moisture is draining properly.

If your HVAC systems run on natural gas, make sure you know where your gas shut off valve is in case you need to close it. You should also make sure to keep an adjustable wrench handy for this purpose. If you ever smell gas, follow the steps below:

Evacuate your home.

Once everyone is safely out of the home, shut off the gas supply from the external shut off valve (this will be located near your gas meter).

Call the utility company or emergency service to report the leak.

Types of Air ConditionersMost residential air conditioning systems are electric compressor cycle systems. This type system includes the basic window or through-the-wall unit, as well as central (whole house) air conditioning systems.
Central air conditioning systems are typically either packaged units, which have all major components in one housing (similar to a room-style unit), or split systems, which have a portion of the system in a cabinet outdoors and a blower and other components in an indoor air handler cabinet or within the basic cabinet of a furnace. Regardless of the style of the system, the basic components and method of operation are similar for all electric compression-cycle systems. The major elements are an evaporator coil, a condenser coil, fans to circulate air over both coils, tubing to carry a refrigerant between the two coils, a compressor to move the refrigerant through the system, and a metering device to regulate the rate of refrigerant flow.Principles of Air Conditioner OperationAir conditioning systems use several basic principles of physics to remove heat from within a house:

1. A refrigerant absorbs heat when it changes from a liquid to a gas
2. A refrigerant releases heat when it changes from a gas to a liquid
3. Heat moves from a medium at a high temperature to a medium at a lower temperature.

As the liquid refrigerant passes through an expansion device into the evaporator it expands to a gas. At the same time, it absorbs heat from the household air, which is forced by the air handler fan through the evaporator coil. As this heat transfer takes place, the temperature of the household air becomes noticeably cooler and is forced through air ducts to the rooms of the house. The refrigerant, which vaporizes into a gas in the evaporator, is pulled through the tubing into the compressor where it is compressed to a high-temperature, high-pressure gas. This gaseous refrigerant then passes into the condenser coil where it gives up heat to the relatively cooler outdoor air, which is forced across the coil by second fan. In the process, the refrigerant condenses back to a liquid and is ready to begin another cycle.

Proper Sizing of Air Conditioner for the HomeOne other issue to consider is that an air conditioning system not only removes heat from the air, but it also dehumidifies the air. For comfort cooling, a balance of temperature and humidity must be maintained. This means that the unit must be sized properly so that it runs long enough to dehumidify the air before the thermostat temperature settings are satisfied. An oversized system in a hot, humid climate will not maintain the proper comfort level, as the air will be cooled before a reasonable humidity level is attained.

Adequate airflow is important for the proper operation of an air conditioning system. Dirty filters and blocked or improperly positioned air inlets (returns) and outlets (supply registers) will result in imbalanced air distribution and uneven cooling. At least one return needs to be positioned near the ceiling. Central air conditioning systems do not require a burdensome amount of maintenance, but some basic attention is required if the unit’s maximum economic life span is to be achieved. The first major element that may require replacement is usually the compressor.

Unfortunately, it is also the most expensive component of the system. Manufactures typically provide five-year warranties on the original compressor, but with system maintenance most compressors will last well beyond that period.